title: Prevalence and risk factors of Helicobacter pylori infection in Korea: nationwide multicenter study over 13 years.
abstract: BACKGROUND
  The aim of this study was to evaluate the time trend of seropositivity of Helicobacter pylori (H. pylori) over the period of 13 years in an asymptomatic Korean population, and investigate associated risk factors.
  
  
  METHODS
  This cross-sectional nationwide multicentre study surveyed anti-H. pylori IgG antibodies in 19,272 health check-up subjects (aged [greater than and equal to]16 years) in 2011. Risk factors for H. pylori infection were investigated using logistic regression. Seropositivity in asymptomatic subjects without H. pylori eradication was compared between the years 1998 and 2005. Birth cohort effects were also evaluated.
  
  
  RESULTS
  After exclusion of subjects with a history of H. pylori eradication therapy (n = 3,712, 19.3%) and gastric symptoms (n = 4,764, 24.7%), the seroprevalence of H. pylori infection was 54.4% in 10,796 subjects. This was significantly lower than the seroprevalence of 59.6% in 2005 and that of 66.9% in 1998, and this decrease of seropositivity of H. pylori became widespread across all ages and in most areas of the country. This decreasing trend could be explained by cohort analysis. All younger birth cohorts had a lower seroprevalence of H. pylori than older birth cohorts at the same age. Decreased seroprevalence within the same birth cohorts also accounted for this phenomenon. Clinical risk factors of H. pylori infection were higher cholesterol level ([greater than and equal to] 240 mg/dl) (OR = 1.33; 95% CI = 1.14-1.54), male gender, older age, low income, and residence in a rural area.
  
  
  CONCLUSIONS
  A decreasing trend of H. pylori seroprevalence due to a birth cohort effect requires further studies on its related human host factors as well as socio-economic and hygienic factors. In addition, the relationship between H. pylori infection and high cholesterol level needs more investigation regarding underlying pathogenesis.
authors.affiliation: Seoul National University Hospital, Healthcare System Gangnam Center, Healthcare Research Institute, Seoul, Korea.
authors.forename: Seon Hee
authors.initials: SH
authors.lastname: Lim
authors.forename: Jin-Won
authors.initials: JW
authors.lastname: Kwon
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.forename: Gwang Ha
authors.initials: GH
authors.lastname: Kim
authors.forename: Jung Mook
authors.initials: JM
authors.lastname: Kang
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Park
authors.forename: Jeong Yoon
authors.initials: JY
authors.lastname: Yim
authors.forename: Heung Up
authors.initials: HU
authors.lastname: Kim
authors.forename: Gwang Ho
authors.initials: GH
authors.lastname: Baik
authors.forename: Geom Seog
authors.initials: GS
authors.lastname: Seo
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Shin
authors.forename: Young-Eun
authors.initials: YE
authors.lastname: Joo
authors.forename: Joo Sung
authors.initials: JS
authors.lastname: Kim
authors.forename: Hyun Chae
authors.initials: HC
authors.lastname: Jung
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D016481:Helicobacter Infections / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007182:Income; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012424:Rural Population; D016036:Seroepidemiologic Studies; D012737:Sex Factors; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D002784:Cholesterol